1. Field of the Invention
The present invention relates to a temperature compensated spectroscope and an optical apparatus.
2. Description of the Related Art
A large number of apparatuses in which, spectroscopic technique is used have hitherto been proposed. A spectroscopic instrument in which, a diffraction grating is used, has been disclosed in Patent literature 1, and an endoscope in which, a diffraction grating is used, has been disclosed in Patent literature 2. Moreover, a spectromicroscope by using a prism and a digital micro mirror has been disclosed in Patent literature 3.
Moreover, a basic structure of a wavelength selective switch has been disclosed in Patent literature 4, in the name of optical add-drop multiplexer.
Here, the wavelength selective switch is a device to be placed in a node in an ROADM (reconfigurable optical add-drop multiplexer) (a system or a technology used in a large-capacity network, in which, a wavelength-multiplexed optical signal is split/inserted as an optical signal as it is), and is an optical switch which carries out for each wavelength, switching of a transmission path of a light signal which is being wavelength-multiplexed.
By the wavelength selective switch in each node, it is possible to fetch an optical signal of an arbitrary wavelength from the optical signal which has been wavelength-multiplexed, and to mix light of an arbitrary wavelength with the optical signal which has been wavelength-multiplexed. Even in this wavelength selective switch, a diffraction grating is used.
Moreover, a light dispersing device which includes a diffraction grating as a dispersive element, which is insensitive to temperature, and of which, an angle of output does not change, has been disclosed in Patent literature 5.    (Patent Literature 1)
Japanese Patent Application Laid-open Publication No. 2007-187550;    (Patent Literature 2)
Japanese Patent Application Laid-open Publication No. 2007-135989;    (Patent Literature 3)
Japanese Patent Application Laid-open Publication No. 2000-199855;    (Patent Literature 4)
Japanese Patent No. 3937403 Specification;    (Patent Literature 5)
Japanese National Publication of translated version No. 2003-509714